1. Field
The exemplary embodiments disclosed herein relate to a spectral detector capable of analyzing a spectrum of incident light and an image sensor including the spectral detector.
2. Description of the Related Art
A method under current discussion as a noninvasive glucose measurement method is an analysis method based on a spectrum of light that is radiated to skin and then scattered from the skin, and includes a biometric signal. Recently, with improvement in performance of mobile devices such as cellular phones, various attempts have been made to integrate a noninvasive biometric sensor in a mobile device. To this end, a need exists for development of a micro spectral detector that is mountable in a mobile device.
For example, a spectral detector using a linear variable filter (LVF) scheme may have a structure in which a spacer having a gradually changing thickness is disposed on multiple photodiode pixels. By employing a principle that a transmissive wavelength changes with the thickness of the spacer, light in a different wavelength region may be sensed in a different pixel. A spectral detector using a filter array scheme has a structure in which a band-pass filter having a different transmissive band for a different photodiode pixel is disposed.
Recently, research has been conducted on a micro spectral detector based on silicon photonics. The silicon-photonics-based micro spectral detector may be manufactured to a small size in the form of a semiconductor chip, and thus is favorable to miniaturization.